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Agrivoltaics (Agri-PV, AV) – the joint use of land for the production of agricultural products and energy – has recently been rapidly gaining popularity, as it can significantly increase income per unit of land area. In a broad sense, AV systems can include converters of not only solar, but also energy from any other local renewable source, including bioenergy. Current approach to AV represents an evolutionary development of agroecology and integrated PV power supply to the grid. That results in nearly doubled income per unit area. While AV could provide a basis for revolution in large-scale unmanned precision agriculture and smart farming which is impossible without on-site power supply, chemical fertilisation and pesticides reduction, and yield processing on-site. These approaches could change the logistics and the added value production chain in agriculture dramatically, and so, reduce its carbon footprint. Utilisation of decommissioned solar panels in AV could make the technology twice cheaper and postpone the need for bulk PV recycling. Unlike the mainstream discourse on the topic, this review feature is in focusing on the possibilities for AV to be stronger integrated into agriculture that could also help in relevant legal collisions (considered as neither rather than both components) resolution.

An increasing global population has meant aquaculture, one of the fastest growing food industry sectors, faces significant sustainability challenges as it tries to address the rising global protein demand. In many sectors, production is underpinned by fishmeal as dietary ingredient, but this is a finite resource with competing users from the poultry and livestock industries. Alternatively, some (planktonic) aquatic species, especially brine shrimp Artemia, can be produced using agricultural waste to provide food or biomass to support increasing aquaculture demand. This review investigates research and production of Artemia using agricultural waste. Various systems used for Artemia production in inoculated ponds are analysed and discussed to provide options for environmentally sustainable food systems that can be applied from either an artisanal level in developing countries with a considerable labour force, or in intensive systems in countries with large volumes of under-utilised resources, for example, sugar/alcohol-based waste and inland saline areas. Using agricultural waste, single cell protein production in a separate aerobic digester can be a simple, continuous food source for Artemia to enable daily biomass harvest. This could then be used as a fishmeal replacement or possibly for human consumption to promote a circular economy by remediating waste to produce protein, like a food production mine.

Grasses, legumes and green plant wastes represent a ubiquitous feedstock for developing a bioeconomy in regions across Europe. These feedstocks are often an important source of ruminant feed, although much remains unused or underutilised. In addition to proteins, these materials are rich in fibres, sugars, minerals and other components that could also be used as inputs for bio-based product development. Green Biorefinery processes and initiatives are being developed to better capitalise on the potential of these feedstocks to produce sustainable food, feed, materials and energy in an integrated way. Such systems may support a more sustainable primary production sector, enable the valorisation of green waste streams, and provide new business models for farmers. This review presents the current developments in Green Biorefining, focusing on a broad feedstock and product base to include different models of Green Biorefinery. It demonstrates the potential and wide applicability of Green Biorefinery systems, the range of bio-based product opportunities and highlights the way forward for their broader implementation. While the potential for new products is extensive, quality control approval will be required prior to market entry.

Natural gas, biogas and alcohols are alternative fuels for spark ignition engines which can be used for reducing exhaust emissions and improving performance metrics. At the first stage of the study, a pilot scale biogas system was built, and biogas was produced from a mixture of manure and water called slurry, consisting of 40% cattle manure, 35% water, 17% whey and 8% poultry manure by co-fermentation method. Scrubbing and desulfurization were applied to remove the harmful gasses (CO2, H2S) from the produced biogas in two stages. In the end of the purification process, biogas with a CH4 content of 51%, 57% and 87% was produced. In the second stage, these biogas fuels were used in an SI engine, and their impacts on performance and combustion characteristics were investigated experimentally. A 4-cylinder, 4-stroke, water cooled SI engine with an 11:1 compression ratio was used in the experiments. Tests were conducted at various loads and constant speed. Results showed that daily amount of mean biogas production has reached 1.6 m(3)/day and biogas methane content has reached 72%. In engine tests, as the methane ratio in biogas increases, cylinder pressure and exhaust temperature values increase and brake specific fuel consumption decreases. Karabuk UniversityKarabuk University [KBU-BAP-14/2-DR-004] The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Karabuk University (grant number KBU-BAP-14/2-DR-004). WOS:000720306000001 2-s2.0-85119421966

Abstract Enzymes are high value industrial bio-catalysts with extensive applications in a wide range of manufacturing and processing sectors, including the agricultural, food and household care industries. The catalytic efficiency of enzymes can be several orders higher compared to inorganic chemical catalysts under mild conditions. However, the nutrient medium necessary for biomass culture represents a significant cost to industrial enzyme production. Activated sludge (AS) is a waste product of biological wastewater treatment and consists of microbial biomass that degrades organic matter by producing substantial quantities of hydrolytic enzymes. Therefore, enzyme recovery from AS offers an alternative, potentially viable approach to industrial enzyme production. Enzyme extraction from disrupted AS flocs is technically feasible and has been demonstrated at experimental-scale. A critical review of disruption techniques identified sonication as potentially the most effective and suitable method for enzyme extraction, which can be scaled up and is a familiar technology to the water industry. The yields of different enzymes are influenced by wastewater treatment conditions, and particularly the composition, and can also be controlled by feeding sludge with specific target substrates. Nevertheless, hydrolytic enzymes can be effectively extracted directly from waste AS without specific modifications to standard wastewater treatment processes. Purification, concentration and stabilisation/immobilisation techniques can also greatly expand the industrial application and increase the economic value and marketability of enzyme products extracted from AS. Concentrated and purified AS enzymes could readily substitute inorganic and/or commercial bioenzyme catalysts in many industrial applications including, for example, leather processing, and in detergent and animal feed formulation. Enzyme extraction from AS therefore offers significant economic benefits to the Water Industry by recovering valuable resources from wastewater. They can also optimise important waste treatment processes, such as the anaerobic digestion (AD) of sewage sludge, increasing biogas and renewable energy production. The enzyme-extracted sludge exhibits improved treatment properties, such as increased settleability, dewaterability, and anaerobic digestibility for biogas production, assisting sludge management by wastewater treatment plants (WWTPs) and enabling the further utilisation of the residual sludge. Graphic Abstract

Summary Pure (single) cultures of microorganisms and mixed microbial communities (microbiomes) have been important for centuries in providing renewable energy, clean water and food products to human society and will continue to play a crucial role to pursue the Sustainable Development Goals. To use microorganisms effectively, microbial engineered processes require adequate control. Microbial communities are shaped by manageable deterministic processes, but also by stochastic processes, which can promote unforeseeable variations and adaptations. Here, we highlight the impact of stochasticity in single culture and microbiome engineering. First, we discuss the concepts and mechanisms of stochasticity in relation to microbial ecology of single cultures and microbiomes. Second, we discuss the consequences of stochasticity in relation to process performance and human health, which are reflected in key disadvantages and important opportunities. Third, we propose a suitable decision tool to deal with stochasticity in which monitoring of stochasticity and setting the boundaries of stochasticity by regulators are central aspects. Stochasticity may give rise to some risks, such as the presence of pathogens in microbiomes. We argue here that by taking the necessary precautions and through clever monitoring and interpretation, these risks can be mitigated., In this review paper, we highlight the impact of stochasticity in single culture and microbiome engineering. Stochasticity may give rise to some risks, such as the presence of pathogens in microbiomes. We argue here that by taking the necessary precautions and through clever monitoring and interpretation, these risks can be mitigated.

In this study, the effects of different pretreatment methods on the biochemical methane potential (BMP) of hurds from two hemp species, namely Narlisaray (NS) and Futura 75 (F), were investigated. The effect of pretreatment on BMP was discussed on the basis of the change in the chemical constituents of the raw material. The highest BMP yields of 272 mL CH4/g VS (F) and 218 mL CH4/g VS (NS) were obtained when the combined alkaline and thermal pretreatment was applied which resulted in the highest amount of hemicellulose degradation. (143% for alkaline and 74% for thermal, respectively, higher than those from raw hurds). It was found that BMP yields and the efficiency of pretreatment for two hemp species depended on genotypes, not on the content of chemical constituents of raw material. Additionally, the first-order kinetic model and the modified Gompertz model were simultaneously used to estimate the CH4 yield results of hurd. The first-order kinetic model resulted in the best fit [R-2 >= 0.96; root mean square error (RMSE) = 0.98; RMSE, TUBITAK [219M123], This research was funded by TUBITAK grant no 219M123 in behalf of Prof. Yanik.

Using insects, notably black soldier fly (BSF), is becoming one of the emerging technologies to valorize agrifood waste into high-value products, such as proteins for animal feed. Its market is expected to grow more rapidly following the new European legislation extending larvae protein use in poultry farming. The anticipated increase in larvae protein also results in a parallel increase in frass, a residue leftover after rearing the larvae and selling as a biofertilizer. Little is known about the impacts of frass made from different feedstocks used for raising the larvae on plant growth and soil quality. We set up an incubation and pot experiment to understand their effect on plant growth and soil quality and tested seven frass fertilizers made from various types of food waste and anaerobic digestate and potato pulp as reference materials using maize as a test plant. We found that the effect of frass on N availability and soil microbial quality significantly (p < 0.05) varied depending on the feedstock used for rearing the BSF larvae. N immobilization occurred up to more than 70 days, and 4–20% net N was released at the end of the 103-day-long experiment. In line with N availability dynamics, most of the frass treatments did not significantly increase the plant growth. All frasses significantly increased the microbial biomass C and enzyme activities. About 56–70% of the applied C in frass is estimated to be stable in the soil. Our data confirm that frass is a valuable product to improve soil quality but need to be applied with N sources that are readily available to avoid nutrient shortage during plant growth.

Poultry manure (PM) has become a serious environmental problem due to large scale of industrial production and unsustainable management, causing emissions of greenhouse gases (GHGs), odors, leakage of nutrients as well as inorganic, organic and biological pollutants. The main goal of this review was to get a better understanding of carbon, nitrogen, and phosphorous cycles in processing of poultry manure with the most common technologies such as composting, anaerobic digestion, or thermal processes, e.g. pyrolysis. The carbon contained in organic matter (ca. 31%) is mineralized and humified under aerobic conditions (matter recovery) and/or converted into biogas under anaerobic conditions (energy recovery). PM as a feedstock for pyrolysis to obtain biochar may effectively store and prevent C, thus contributing to climate change abatement. During composting, nitrogen is reduced from the compost mixture by leachates in the form of NH4+, NO3− or gaseous emissions of NH3, N2O, N2. The C/N ratio is also decisive parameter. Most environmental threats of unmanaged PM result from ammonia and nitrous oxide emissions, being higher for PM compared to cattle and cow manure independently of technological processes. The phosphorous in PM is mainly inorganic (32-84%). Using untreated manure as a fertilizer does not allow taking up high doses of phosphorus contained in poultry manure, so the excess accumulates in the soil and then leaches into groundwater. Biochar and struvite are an alternative to storage and source of high concentrations of phosphorous. Cycles of carbon, nitrogen and phosphorus are an integral effect of technologies used for PM management.

Sustainable provision of chemicals and materials is undoubtedly a defining factor in guaranteeing economic, environmental, and social stability of future societies. Among the most sought-after chemical building blocks are volatile fatty acids (VFAs). VFAs such as acetic, propionic, and butyric acids have numerous industrial applications supporting from food and pharmaceuticals industries to wastewater treatment. The fact that VFAs can be produced synthetically from petrochemical derivatives and also through biological routes, for example, anaerobic digestion of organic mixed waste highlights their provision flexibility and sustainability. In this regard, this review presents a detailed overview of the applications associated with petrochemically and biologically generated VFAs, individually or in mixture, in industrial and laboratory scale, conventional and novel applications.

Resource efficiency analysis is an important tool in the chemical sector to evaluate the performance of new process concepts. However, such analysis does not account for the renewability and circularity of resources. Therefore, a resource efficiency and use analysis, including those two aspects, is proposed in this paper. A renewability indicator and recovery indicator were calculated as a measure for renewability and circularity, respectively. In addition, the resource efficiency was determined at different levels. At the life cycle level, the cumulative exergy extraction of the natural environment method was applied and the cumulative degree of perfection, including waste-as-resources, was calculated. Exergy calculations were used to determine the exer-getic efficiency at process chain and plant level and to identify inefficiencies. A new propanol production concept, using biogas (scenario BG), marginal gas (scenario MG) and associated gas (scenario AG), was selected as a case study. Exergetic efficiencies are high at the individual process level (between 90 and 100%). However, the preceding biogas production in scenario BG is inefficient (exergetic efficiency of 12%). The exergetic effi-ciency at the process chain level amounts to 45-68% due to the high exergy content of the recycling stream and the low conversion of methane into propanol per pass. Scenario AG has the highest cumulative degree of perfection (including waste-as-resources) compared to the other scenarios (28% against 6 and 14% in scenario BG and MG). In contrast, when looking at both renewability, circularity and efficiency, scenario BG is identified as the most promising scenario. Thus, this study shows that it is important to include those three aspects in resource efficiency analysis. Finally, implementing renewable electricity production and heat integration in the process concept may increase the resource efficiency.

The carbon (C) and nitrogen (N) mineralisation rates of five digestates were studied and compared with pig slurry, compost, and a solid fraction of digestate in aerobic incubation experiments. The objective was to identify the most relevant drivers of C and N mineralisation based on the physicochemical properties of the products. Net organic nitrogen mineralisation of digestates (Nmin,net) was on average 30%, although the range was relatively wide, with digestate from pig manure (39%) reaching double the value of digestate from sewage sludge (21%). The total carbon to total nitrogen (TC:TN) (r = −0.83, p < 0.05) and ammonium nitrogen to total nitrogen (NH4+-N:TN) (r = 0.83, p < 0.05) ratios of the products were strongly correlated with Nmin,net, adequately mirroring the expected fertilising potential of the products. The digestates had C sequestration values between 50 and 81% of applied total organic carbon (TOC), showcasing their potential to contribute to C build-up in agricultural soils. The carbon use efficiency of the amended soils was negatively correlated with dissolved organic carbon (DOC) (r = −0.75, p < 0.05) suggesting that catabolic activities were promoted proportionately to the DOC present in these products. Ratios of DOC:TOC (r = −0.88, p < 0.01) and TC:TN (r = 0.92, p < 0.01) were reliable predictors of the fraction of C that would remain one year after its incorporation and thus could be used as simple quality parameters to denote the C sequestration potential of digestates prior to their use in the field.

Ex-situ biomethanation (CO2 + 4H2 → CH4 + 2H2O) can simultaneously achieve renewable electricity storage and CO2 valorisation. However, fluctuations in variable renewable electricity may lead to intermittent hydrogen supply, which is shown to adversely affect microbial activity and performance of the biomethanation process. Carbonaceous materials may act as an abiotic additive to enhance microbial robustness and improve system performance. Nanomaterial graphene and pyrochar were compared to assess their effects on biomethanation systems with an intermittent supply of hydrogen. Results revealed that intermittent gas supply caused deterioration in the restart performance with only 66% of theoretical methane production obtained in the control compared with 84% under steady state conditions. The addition of graphene in biomethanation led to 78% of the theoretical methane production after repetitive intermittent supply; this improvement is postulated to be due to its high electrical conductivity and large specific surface (500 m2/g). In comparison, pyrochar amendment did not lead to a significant improvement in upgrading performance. Microbial analysis showed that the OTUs affiliated to bacteria withinin the order SHA-98 (42.9% in abundance) and archaea from the genus Methanothermobacter (99%) may result in the establishment of a new syntrophic relationship to improve the robustness of biomethanation process.

The European Commission requested EFSA to assess if different thermal processes achieve a 5 log10 reduction in Enterococcus faecalis or Salmonella Senftenberg (775W) and (if relevant) a 3 log10 reduction in thermoresistant viruses (e.g. Parvovirus) as well as if different chemical processes achieve a 3 log10 reduction of eggs of Ascaris sp., in eight groups of Category 2 and 3 derived products and animal by-products (ABP). These included (1) ash derived from incineration, co-incineration and combustion; (2) glycerine derived from the production of biodiesel and renewable fuels; (3) other materials derived from the production of biodiesel and renewable fuels; (4) hides and skins; (5) wool and hair; (6) feathers and down; (7) pig bristles; and (8) horns, horn products, hooves and hoof products. Data on the presence of viral hazards and on thermal and chemical inactivation of the targeted indicator microorganisms and biological hazards under relevant processing conditions were extracted via extensive literature searches. The evidence was assessed via expert knowledge elicitation. The certainty that the required log10 reductions in the most resistant indicator microorganisms or biological hazards will be achieved for each of the eight groups of materials mentioned above by the thermal and/or chemical processes was (1) 99-100% for the two processes assessed; (2) 98-100% in Category 2 ABP, at least 90-99% in Category 3 ABP; (3) 90-99% in Category 2 ABP; at least 66-90% in Category 3 ABP; (4) 10-66% and 33-66%; (5) 1-33% and 10-50%; (6) 66-90%; (7) 33-66% and 50-95%; (8) 66-95%, respectively. Data generation on the occurrence and reduction of biological hazards by thermal and/or chemical methods in these materials and on the characterisation of the usage pathways of ABP as organic fertilisers/soil improvers is recommended. ispartof: EFSA JOURNAL vol:19 issue:12 ispartof: location:United States status: published

Currently, due to the rapid growth of urbanization and industrialization in developing countries, a large volume of wastewater is produced from industries that contain chemicals generating high environmental risks affecting human health and the economy if not treated properly. Consequently, the development of a sustainable low-cost wastewater treatment approach has attracted more attention of policymakers and scientists. The present review highlights the recent applications of biochar in removing organic and inorganic pollutants present in industrial effluents. The recent modes of preparation, physicochemical properties and adsorption mechanisms of biochar in removing organic and inorganic industrial pollutants are also reviewed comprehensively. Biochar showed high adsorption of industrial dyes up to 80%. It also discusses the recent application and mechanism of biochar-supported photocatalytic materials for the degradation of organic contaminants in wastewater. We reviewed also the possible optimizations (such as the pyrolysis temperature, solution pH) allowing the increase of the adsorption capabilities of biochar leading to organic contaminants removal. Besides, increasing the pyrolysis temperature of the biochar was seen to lead to an increase in its surface area, while it decreases their amount of oxygen-containing functional groups, consequently leading to a decrease in the adsorption of metal (loid) ions present in the medium. Finally, the review suggests that more research should be carried out to optimize the main parameters involved in biochar production and its regeneration methods. Future efforts should be also carried out towards process engineering to improve its adsorption capacity to increase the economic benefits of its implementation.

Although biogas technologies in Brazil have a huge potential and a long history few studies have examined biogas in Brazil as a technological field. Accordingly, this paper aims to understand which conditions enabled or constrained the diffusion of biogas technologies. More specifically, this research applies and adapts the Technological Innovation System (TIS) framework to examine biogas-specific and context-related conditions as well as their interplay. Data were collected by performing an event history analysis from 1979 to 2016 along with 24 in-depth expert interviews. Our findings indicate that the evolution of geographically embedded sectoral regulations and infrastructures as well as their interactions have been responsible for major changes in the biogas field in Brazil. By demonstrating how this occurred, this research has opened up new possibilities to promote biogas technologies in Brazil. This study also provides an important analytical method that focuses on exploring activities and their background conditions to consider contextual influences in TIS. Consequently, three major ways of contextual influences for TIS studies are suggested – evolution of contextual structures, interaction of contextual structures and translation of external events by these interactions.

This paper proposes the use of modified biochar, derived from Sawdust (SD) biomass using sonication (SSDB) and Ozonation (OSDB) processes, as an additive for biogas production from green algae Cheatomorpha linum (C. linum) either individually or co-digested with natural diet for rotifer culture (S. parkel). Brunauer-Emmett-Teller (BET), Fourier-Transform Infrared (FTIR), thermal-gravimetric (TGA), and X-ray diffraction (XRD) analyses were used to characterize the generated biochar. Ultrasound (US) specific energy, dose, intensity and dissolved ozone (O3) concentration were also calculated. FTIR analyses proved the capability of US and ozonation treatment of biochar to enhance the biogas production process. The kinetic model proposed fits successfully with the data of the experimental work and the modified Gompertz models that had the maximum R2 value of 0.993 for 150 mg/L of OSDB. The results of this work confirmed the significant impact of US and ozonation processes on the use of biochar as an additive in biogas production. The highest biogas outputs 1059 mL/g VS and 1054 mL/g VS) were achieved when 50 mg of SSDB and 150 mg of OSDB were added to C. linum co-digested with S. parkle.

The dairy industry generates excessive amounts of waste and by-products while it gives a wide range of dairy products. Alternative biotechnological uses of these wastes need to be determined to aerobic and anaerobic treatment systems due to their high chemical oxygen demand (COD) levels and rich nutrient (lactose, protein and fat) contents. This work presents a critical review on the fermentation-engineering aspects based on defining the effective use of dairy effluents in the production of various microbial products such as biofuel, enzyme, organic acid, polymer, biomass production, etc. In addition to microbial processes, techno-economic analyses to the integration of some microbial products into the biorefinery and feasibility of the related processes have been presented. Overall, the inclusion of dairy wastes into the designed microbial processes seems also promising for commercial approaches. Especially the digestion of dairy wastes with cow manure and/or different substrates will provide a positive net present value (NPV) and a payback period (PBP) less than 10 years to the plant in terms of biogas production.

This study is the first work that evaluated the effectiveness of unmodified (SD) and modified biochar with ammonium hydroxide (SD-NH2) derived from sawdust waste biomass as an additive for biogas production from red algae Pterocladia capillacea either individually or in combination with hematite α-Fe2O3 NPs. Brunauer, Emmett, and Teller, Fourier transform infrared, thermal gravimetric analysis, X-ray diffraction, transmission electron microscopy, Raman, and a particle size analyzer were used to characterize the generated biochars and the synthesized α-Fe2O3. Fourier transform infrared (FTIR) measurements confirmed the formation of amino groups on the modified biochar surface. The kinetic research demonstrated that both the modified Gompertz and logistic function models fit the experimental data satisfactorily except for 150 SD-NH2 alone or in combination with α-Fe2O3 at a concentration of 10 mg/L. The data suggested that adding unmodified biochar at doses of 50 and 100 mg significantly increased biogas yield compared to untreated algae. The maximum biogas generation (219 mL/g VS) was obtained when 100 mg of unmodified biochar was mixed with 10 mg of α-Fe2O3 in the inoculum.

International audience; Even though sulfur compounds and their transformations may strongly affect wastewater treatment processes,their importance in water resource recovery facilities (WRRF) operation remains quite unexplored, notablywhen it comes to full-scale and plant-wide characterization. This contribution presents afirst-of-a-kind, plant-wide quantification of total sulfur massflows for all water and sludge streams in a full-scale WRRF. Because ofits important impact on (post-treatment) process operation, the gaseous emission of sulfur as hydrogen sulfide(H2S) was also included, thus enabling a comprehensive evaluation of sulfurflows. Data availability and qualitywere optimized by experimental design and data reconciliation, which were applied for thefirst time to total sul-furflows. Total sulfurflows were successfully balanced over individual process treatment units as well as theplant-wide system with only minor variation to their original values, confirming that total sulfur is a conservativequantity. The two-stage anaerobic digestion with intermediate thermal hydrolysis led to a decreased sulfur con-tent of dewatered sludge (by 36%). Higher (gaseous) H2S emissions were observed in the second-stage digester(42% of total emission) than in thefirst one, suggesting an impact of thermal treatment on the production of H2S.While the majority of sulfur massflow from the influent left the plant through the treated effluent (> 95%), thesulfur discharge through dewatered sludge and gaseous emissions are critical. The latter are indeed responsiblefor odour nuisance, lower biogas quality, SO2emissions upon sludge combustion and corrosion effects.

International audience; Phytoattenuation combines phytoextraction or phytostabilization with the economic valorization of the biomass produced on the contaminated soil. Sorghum bicolor is a suitable crop for this strategy, as it is known to be metal-tolerant and can be used for biogas or bioethanol production or in strategies toward biofortification. In the current investigation, two cultivars, Biomass 133 and Trudan Headless (HL), were studied in a metal-contaminated (Cd, Pb, Zn) field site located in northern France to assess their potential use in a phytoattenuation strategy. The biomass yield and the metal transfer in the produced biomass were monitored in three plots with different pollution levels. Both cultivars were tolerant to high levels of metal pollution in field conditions, with yields similar to that obtained on uncontaminated sites. Neither of the cultivars changed the metal mobility of the soil and both exhibited a metal-excluder behavior. Nevertheless, Cd concentration in the aboveground part of Trudan HL, and of Biomass 133 to a lesser extent, could restrict their use in some valorization options. However, biogas production was possible with the produced biomass, indicating anaerobic digestion to be a possible valorization route for sorghum grown on contaminated sites.

Anaerobic digestion of nitrogen (N) rich substrates might be hindered when ammonia (NH3) formation reaches toxic levels for methanogenic microorganisms. One possible strategy to avoid inhibiting conditions is the removal of NH3 from digestate by stripping and scrubbing technology and by recirculating N depleted digestate back to the digester. This study aimed to i) monitor the performance (mass and energy balances) of a full scale digestate processing cascade that includes an innovative vacuum side stream NH3stripping and scrubbing system, ii) assess the production cost of ammonium sulphate (AS) solution and iii) evaluate its fertiliser quality. The use of gypsum to recover NH3 in the scrubbing unit, instead of the more common sulphuric acid, results in the generation of AS and a fertilising liming substrate. Mass and nutrient balances indicated that 57% and 7.5% of ammonium N contained in digestate was recovered in the form of a 22% AS and liming substrate, respectively. The energy balance showed that about 3.8 kWhel and 59 kWhth were necessary to recover 1 kg of N in the form of AS. Furthermore, the production cost of AS, including both capital and operational costs, resulted to be 5.8 € t−1 of digestate processed. According to the fertiliser quality assessment, this technology allows for the recovery of NH3in the form of salt solutions that can be utilised as a substitute for synthetic mineral nitrogen fertilisers., Highlights • A novel ammonia stripping process was monitored at a fullscale digestate processing facility. • 57% of ammonium nitrogen contained in digestate was recovered as ammonium sulphate (22%). • Nitrogen in recovered ammonium sulphate is present entirely in mineral form. • The cost for the nitrogen recovery system amounts to 5.8 € per tonne of digestate processed. • Biobased ammonium sulphate represents an interesting alternative to synthetic nitrogen fertilisers.

This work evaluates the release of phosphorus contained in the digestate from the anaerobic digestion of pig manure, through an acidification process. The objective of this acidification is to increase the amount of phosphorus available in the digestate liquid fraction and, subsequently, recover this element by chemical precipitation in the form of struvite or calcium phosphate. Two digestate samples (one fresh and one old) were studied and treated by adding various amounts of sulphuric acid to the different digestate fractions (raw digestate, solid fraction and liquid fraction). For the raw digestate, phosphorus releases higher than 95% were obtained for pH 4.0. In the last part of the experiment, the influence of acid pre-treatment on the reaction yield of phosphorus precipitation, in the form of struvite or calcium phosphate, was determined. Improvements in reaction yield were obtained up to 15% for struvite and 80% for calcium phosphate, increasing also in 7.5 times the amount of phosphorus available in the digestate liquid fraction, for both cases.

This investigation studies the impact of trace elements supplementation on protein anaerobic conversion into volatile fatty acids (VFAs). Two continuous reactors were operated with two model substrates, casein and gelatin, at acid (pH 5) and neutral (pH 7) conditions, with the addition of macro and micronutrients. Micronutrients increased the acidification degree of both proteins from 40% to 50% to more than 60% only at pH 7, which was consistent with a greater amino acid consumption at neutral conditions. Furthermore, trace elements modified the process selectivity, promoting valeric acids production and other variations dependant on protein composition. Isomerisation and chain elongation processes were identified as a consequence of the observed deviations between amino acid consumption and VFA production. Overall, this study demonstrated that the supplementation of micronutrients can be useful to enhance and steer the anaerobic fermentation of protein-rich streams This project has received funding from the Spanish Government through the European Union’s ERA-IB programme under grant agreement number PCIN-2016-102 and from the Spanish Ministry of Education (FPU14/05457). The authors belong to a Galician Competitive Research Group (ED431C2017/029; ED431E 2018/01), co-funded by Xunta de Galicia (Spain) and the European Regional Development Fund (ERDF-EU) SI

Correction Resources, Conservation and Recycling Volume 174 Article Number 105738 DOI10.1016/j.resconrec.2021.105738 Published NOV 2021 Although a circular economy promotes economic and environmental benefits, knowledge gaps remain surrounding the application of these concepts to food systems. A better understanding of the connection between different flows of biomass and energy at different spatial scales is needed to facilitate effective transitions towards circular bioeconomies. This study provides a framework for assessing the circularity of food systems, which we exemplify by identifying key steps towards circularity for three contrasting farming regions in Finland. For each of the regions, we quantified the flows of biomass, nutrients and energy. We found large differences in circularity, depending on the chosen indicator. Most biomass and nutrient flows were related to livestock production, which implies that it plays a key role in circular food systems. Current livestock production was found to be connected to national and global food systems through the international feed trade. This trade generates imbalanced nutrient flows between regions and countries, resulting in excess accumulations of nutrients in regions with net imports. In terms of circularity in energy systems, we found that substantial amounts of energy could be produced from manure and plant-based biomasses without causing food-fuel competition in land use. We also observed that, the inclusion of human excreta would further improve recycling but this was significant only in the region with a high population density. Thus, in this study, we propose a concept of nested circularity in which nutrient, biomass and energy cycles are connected and closed across multiple spatial scales.

The management of municipal solid waste is a major logistic and environmental problem worldwide. Nonetheless, the organic fraction of municipal solid waste (OFMSW) is a valuable source of nutrients which can be used for a variety of purposes, according to the Circular Economy paradigm. Among the possible applications, the bioproduction of a biodegradable polyester, poly(3-hydroxybutyrate) [P(3HB)], using OFMSW as carbon platform is a promising strategy. Here, an economic and environmental assessment of bacterial P(3HB) production from OFMSW is presented based on previously published results. The SuperPro Designer (R) software was used to simulate P(3HB) production under our experimental parameters. Two scenarios were proposed depending on the fermentation medium: (1) enzymatic hydrolysate of OFMSW supplemented with glucose and plum waste juice; and (2) basal medium supplemented with glucose and plum waste juice. According to our results, both scenarios are not economically feasible under our experimental parameters. In Scenario 1, the low fermentation yield, the cost of the enzymes, the labour cost and the energy consumption are the factors that most contribute to that result. In Scenario 2, the cost of the extraction solvent and the low fermentation yield are the most limiting factors. The possibility of using process waste as raw material for the generation of other products must be investigated to enhance economic feasibility. From an environmental viewpoint, the photochemical oxidation potential (derived from the use of anisole as extraction solvent) and the generation of acid rain and global warming effect (caused by the burning of fuels for power generation) are the most relevant impacts associated to P(3HB) production under our experimental parameters. Jon Kepa Izaguirre was the recipient of a predoctoral fellowship from the Basque Government

Biogas is one of the most attractive renewable resources due to its ability to convert waste into energy. Biogas is produced during an anaerobic digestion process from different organic waste resources with a combination of mainly CH4 (similar to 50 mol/mol), CO2 (similar to 15 mol/mol), and some trace gasses. The percentage of these trace gases is related to operating conditions and feedstocks. Due to the impurities of the trace gases, raw biogas has to be cleaned before use for many applications. Therefore, the cleaning, upgrading, and utilization of biogas has become an important topic that has been widely studied in recent years. In this review, raw biogas components are investigated in relation to feedstock resources. Then, using recent developments, it describes the cleaning methods that have been used to eliminate unwanted components in biogas. Additionally, the upgrading processes are systematically reviewed according to their technology, recovery range, and state of the art methods in this area, regarding obtaining biomethane from biogas. Furthermore, these upgrading methods have been comprehensively reviewed and compared with each other in terms of electricity consumption and methane losses. This comparison revealed that amine scrubbing is one the most promising methods in terms of methane losses and the energy demand of the system. In the section on biogas utilization, raw biogas and biomethane have been assessed with recently available data from the literature according to their usage areas and methods. It seems that biogas can be used as a biofuel to produce energy via CHP and fuel cells with high efficiency. Moreover, it is able to be utilized in an internal combustion engine which reduces exhaust emissions by using biofuels. Lastly, chemical production such as biomethanol, bioethanol, and higher alcohols are in the development stage for utilization of biogas and are discussed in depth. This review reveals that most biogas utilization approaches are in their early stages. The gaps that require further investigations in the field have been identified and highlighted for future research.

Liquid manure (slurry) from livestock releases methane (CH4) that contributes significantly to global warming. Existing models for slurry CH4 production—used for mitigation and inventories—include effects of organic matter loading, temperature, and retention time but cannot predict important effects of management, or adequately capture essential temperature-driven dynamics. Here we present a new model that includes multiple methanogenic groups whose relative abundance shifts in response to changes in temperature or other environmental conditions. By default, the temperature responses of five groups correspond to those of four methanogenic species and one uncultured methanogen, although any number of groups could be defined. We argue that this simple mechanistic approach is able to describe both short- and long-term responses to temperature where other existing approaches fall short. The model is available in the open-source R package ABM (https://github.com/sashahafner/ABM) as a single flexible function that can include effects of slurry management (e.g., removal frequency and treatment methods) and changes in environmental conditions over time. Model simulations suggest that the reduction of CH4 emission by frequent emptying of slurry pits is due to washout of active methanogens. Application of the model to represent a full-scale slurry storage tank showed it can reproduce important trends, including a delayed response to temperature changes. However, the magnitude of predicted emission is uncertain, primarily as a result of sensitivity to the hydrolysis rate constant, due to a wide range in reported values. Results indicated that with additional work—particularly on the magnitude of hydrolysis rate—the model could be a tool for estimation of CH4 emissions for inventories.

This study provides fundamental insight and offers a promising catalytic hydrothermal method to harness cranberry pomace as a potential bioenergy and/or hydrochar source. The physical and chemical properties of Canadian cranberry pomace, supplied by Fruit d’Or Inc., were examined and the optimum operational conditions, in terms of biocrude yield, were obtained by the I-optimal matrix of Design Expert 11. Afterward, cranberry pomace hydrochar (CPH) and zeolite were separately introduced to the hydrothermal liquefaction (HTL) process to investigate the benefits and disadvantages associated with their catalytic activity. CPH was found to be a better host than zeolite to accommodate cellulosic sugars and showed great catalytic performance in producing hydrocarbons. However, high amounts of corrosive amino and aliphatic acids hinder the practical application of CPH as a catalyst. Alternatively, zeolite, as a commercial high surface area catalyst, had a higher activity for deoxygenation of compounds containing carbonyl, carboxyl, and hydroxyl groups than CPH and resulted in higher selectivity of phenols. Due to the low hydrothermal structural stability, coke formation, and narrow pore size distribution, further activations and modifications are needed to improve the catalytic behavior of zeolite. Our results suggest that a composite composed of CPH and zeolite can resolve the abovementioned limitations and help with the development and commercialization of advanced biofuels from cranberry pomace.

Application of nanomaterials for the treatment of effluents originated from various industrial and non-industrial sources, has been rapidly developed in recent decades. In this situation, there is a need for conclusive studies to identify the current status of the knowledge in this field and to promote the commercialization of such technologies by providing recommendations for future studies. In the present manuscript, a scientometric assessment on the progress made in this field has been performed and the results have been organized and discussed in terms of science statistics, research hotspots and trends, as well as the relevant sustainability aspects. Based on a set of keywords, identified through a pre-literature analysis, a total of 6539 documents were retrieved from the Web of Science (WoS) database and analyzed to achieve the main goals of this study. The results demonstrate that the studies in this field have been initiated since the beginning of the 2000s but were mainly performed in lab and pilot scales. Also, China and Iran were identified as the most contributing countries in this scientific area in terms of the number of publications. Among various types of engineered nanomaterials (ENMs), there has been especial attention for the application of iron-based nanomaterials as well as carbonaceous structures (such as graphene oxide and biochar). Besides, there are not still strong collaborations formed among researchers in this area worldwide. Regarding the research hotspots, the synthesis of green and sustainable nanomaterials (e.g., biosynthesis approaches) has received attention in recent years. The results can also demonstrate that the most widely studied pathway for the removal of pollutants from (waste)waters involves the adsorption of the pollutants using ENMs. Treatment of contaminants of emerging concern (CECs) as well as exploring the mechanisms involved in the treatment of contaminated (waste)waters using ENMs and the possible by-products are considered the current trends in the literature. Regarding the sustainability aspects of ENMs for (waste)water treatment, the results achieved in this study calls for in-depth sustainability studies, which consider parameters such as economic, environmental, and social aspects of nanomaterials utilization for (waste)water treatment purposes, besides the technical parameters, to push transferring such technologies from lab and pilot scales to large and real-scale applications. ispartof: NANOIMPACT vol:22 ispartof: location:Netherlands status: published

Current food production practices tend to damage and deplete soil, diminish biodiversity, and degrade water supplies. For agriculture to become environmentally sustainable and simultaneously increase food output for a growing world population, fundamental changes in agricultural production systems are required. Renewable energy can reduce greenhouse gases (GHGs) but we also need simple, low‐cost approaches to remove atmospheric carbon and sequester it in stable forms. Recycling of digestate from the anaerobic digestion of agricultural and waste materials to soils can sequester atmospheric carbon and provide many other economic, social and environmental benefits. Biogasdoneright™ (BDR) is a set of practices that link biogas production with sustainable agriculture. The BDR approach to sustainable agriculture is being implemented on a large scale in Italy. In this paper, we examine the potential impact of implementing BDR in selected other countries. The biomethane potential in these countries, estimated conservatively, varies from about 10–30% of their current annual natural gas consumption. Biomethane from sequential (double) crops provides by far the greatest fraction of the biomethane potential. Double cropping also drives many of the environmental and economic benefits of BDR systems. Depending on where and how widely it is implemented, the production of biogas in BDR systems could have very significant national‐level impacts. For example, sufficient biomethane could be produced in Argentina to completely eliminate imports of natural gas, equivalent to about 28% of Argentina's 2017 trade deficit. In the USA, renewable biogas could generate electricity equal to nearly all of the electricity currently produced by domestic solar and wind resources. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd

This paper guides decision making in more sustainable urban water management practices that feed into a circular economy by presenting a novel framework for conceptually designing and strategically planning wastewater treatment processes from a resource recovery perspective. Municipal wastewater cannot any longer be perceived as waste stream because a great variety of technologies are available to recover water, energy, fertilizer, and other valuable products from it. Despite the vast technological recovery possibilities, only a few processes have yet been implemented that deserve the name water resource factory instead of wastewater treatment plant. This transition relies on process designs that are not only technically feasible but also overcome various non-technical bottlenecks. A multidimensional and multidisciplinary approach is needed to design water resource factories (WRFs) in the future that are technically feasible, cost effective, show low environmental impacts, and successfully market recovered resources. To achieve that, the wastewater treatment plant (WWTP) design space needs to be opened up for a variety of expertise that complements the traditional wastewater engineering domain. Implementable WRF processes can only be designed if the current design perspective, which is dominated by the fulfilment of legal effluent qualities and process costs, is extended to include resource recovery as an assessable design objective from an early stage on. Therefore, the framework combines insights and methodologies from different fields and disciplines beyond WWTP design like, e.g., circular economy, industrial process engineering, project management, value chain development, and environmental impact assessment. It supports the transfer of the end-of-waste concept into the wastewater sector as it structures possible resource recovery activities according to clear criteria. This makes recovered resources more likely to fulfil the conditions of the end-of-waste concept and allows the change in their definition from wastes to full-fledged products.

Anaerobic pig manure digestion holds potential to contribute to a bio-based economy. This work assesses the stability of the thermophilic mono-digestion process. Thermophilic mono-digestion experiments with (i) fresh liquid pig manure and (ii) the fresh fecal fraction from source separation by a pig housing construction were conducted in semi pilot-scale continuous stirred tank reactors. The effect of separation on the digestion stability was studied by comparing thermophilic mono-digestion of fresh liquid (unseparated) and fresh source separated pig manure. Influencing factors and inhibitors were identified during the experiments. An unstable thermophilic mono-digestion process was observed for fresh liquid pig manure at a digester retention time of 60 days, due to high levels of ammonia and sulfur-containing components. Thermophilic mono-digestion of the fresh fecal fraction was more promising in terms of stability, provided enough time for digestion. In addition, the effect of low temperature (70 degrees C) thermal pre-treatment of manure on the digestion stability was investigated. In the case of liquid pig manure, no improvement in the digestion stability was noted upon thermal pre-treatment. For the fecal fraction, the stability of the thermophilic mono-digestion process did improve. Moreover, thermal treatment and subsequent thermophilic mono-digestion of the fresh fecal fractions from two different farms with a similar pig housing construction suggested an effect of the (organic) dry matter content on the process stability.

Background: Digested sludge is a good source of plant nutrients. However, depending on the feedstock, it might contain heavy metals, metalloids, organic compounds, pathogens, and pharmaceuticals, which can cause adverse effects on crop growth and contaminate the groundwater, soil, and food chain. Scope: The aim of this review is to focus on the potential risks of inorganic and organic contaminants to plant growth, soil, groundwater, and consequently the food chain and environment related to the utilization of digested sludge as a fertilizer on cropland. Conclusions: Inorganic compounds, such as metals and metalloids, in sludge can occasionally cause reductions in soil microbial biomass. In general, the uptake of metals and organic contaminants does not appear to cause a significant hazard to the plants and the concentrations do not surpass the maximum values allowed in soil. Organic compounds, harmful for human health or the environment, are to a large extent decomposed or volatilized from the land treated with sludge, which decreases their leaching into the environment. Many of the organic compounds are lipophilic and can be bound to soil organic matter. In conclusion, the application of sludge on cropland might be a sustainable management practice; however, further investigations are needed to determine the accumulation and persistence of possible hazardous emerging chemicals and pathogens in the environment and formation of harmful intermediate reaction of inorganic and organic compound products.

The 'microbiome' has become a buzzword. Multiple new technologies allow to gather information about microbial communities as they evolve under stable and variable environmental conditions. The challenge of the next decade will be to develop strategies to compose and manage microbiomes. Here, key aspects are considered that will be of crucial importance for future microbial technological developments. First, the need to deal not only with genotypes but also particularly with phenotypes is addressed. Microbial technologies are often highly dependent on specific core organisms to obtain the desired process outcome. Hence, it is essential to combine omics data with phenotypic information to invoke and control specific phenotypes in the microbiome. Second, the development and application of synthetic microbiomes is evaluated. The central importance of the core species is a no-brainer, but the implementation of proper satellite species is an important route to explore. Overall, for the next decade, microbiome research should no longer almost exclusively focus on its capacity to degrade and dissipate but rather on its remarkable capability to capture disordered components and upgrade them into high-value microbial products. These products can become valuable commodities in the cyclic economy, as reflected in the case of 'reversed sanitation', which is introduced here. ispartof: ENVIRONMENTAL MICROBIOLOGY vol:20 issue:6 pages:1991-2000 ispartof: location:England status: published

In this study, an integrated aerobic membrane bioreactor (MBR)-nanofiltration (NF) system has been applied for advanced treatment of Opium processing wastewaters to comply with strict discharge limits. Aerobic MBR treatment was successfully applied to high strength industrial wastewater. In aerobic MBR treatment, a non-fouling unique slot aeration system was designed using computational fluid dynamics techniques. The MBR was used to separate treated effluent from dispersed and non-settleable biomass. Respirometric modeling using MBR sludge indicated that the biomass exhibited similar kinetic parameters to that of municipal activated sludge systems. Aerobic MBR/NF treatment reduced chemical oxygen demand (COD) from 32,000 down to 2,500 and 130 mg/L, respectively. The MBR system provided complete removal of total inorganic nitrogen; however, nearly 50 mgN/L organic nitrogen remained in the permeate. Post NF treatment after MBR permeate reduced nitrogen below 20 mgN/L, providing nearly total color removal. In addition, a 90% removal in the conductivity parameter was reached with an integrated MBR/NF system. Finally, post NF application to MBR permeate was found not to be practical at higher pH due to low flux (3–4 L/m2/hour) with low recovery rates (30–40%). As the permeate pH lowered to 5.5, 75% of NF recovery was achieved at a flux of 15 L/m2/hour.

Energy, water, and waste systems analyzed at a nexus level are important to move toward more sustainable cities. In this paper, the "resilience.io" platform is developed and applied to emphasize on waste-to-energy pathways, along with the water and energy sectors, aiming to develop waste treatment capacity and energy recovery with the lowest economic and environmental cost. Three categories of waste including wastewater (WW), municipal solid waste (MSW), and agriculture waste are tested as the feedstock for thermochemical treatment via incineration, gasification, or pyrolysis for combined heat and power generation, or biological treatment such as anaerobic digestion (AD) and aerobic treatment. A case study is presented for Ghana in sub-Saharan Africa, considering a combination of waste treatment technologies and infrastructure, depending on local characteristics for supply and demand. The results indicate that the biogas generated from waste treatment turns out to be a promising renewable energy source in the analyzed region, while more distributed energy resources can be integrated. A series of scenarios including the business-as-usual, base case, naturally constrained, policy interventions, and environmental and climate change impacts demonstrate how simulation with optimization models can provide new insights in the design of sustainable value chains, with particular emphasis on whole-system analysis and integration.